The importance of automatic identification systems increases particularly in the service sector, in the field of logistics, in the field of commerce and in the field of industrial production. Further applications of identification systems are related to the identification of persons and animals.
In particular contactless identification systems like transponder systems (for instance using an RFID tag) are suitable for a wireless transmission of data in a fast manner and without cable connections that may be disturbing. Such systems use the emission and absorption of electromagnetic waves, particularly in the high frequency domain.
A shortcoming of the RFID technology is that when one or multiple RFID tags are read by a reader device (which may also be denoted as an electromagnetic gate apparatus), the reading rate may depend on the position of the individual RFID tags in relation to the reader device, due to a location dependent or spatially dependent field distribution within an operating range of an electromagnetic gate apparatus. In order to analyze this characteristic, it may desirable to have accurate information regarding the electromagnetic field strength or field geometry of an electromagnetic gate apparatus.